1. Field of the Invention
This invention relates generally to sugar beet harvesters, and pertains more particularly to a spring system for protecting the lifter wheels, paddles and components associated therewith when the lifter wheels are deflected upwardly by a submerged rock.
2. Description of the Prior Art
Although the digging of sugar beets is done at a rather shallow depth (three to four inches being normal), nonetheless the encountering of rocks is sufficiently frequent so as to prove annoying to the farmer because of the cost of replacement parts and the time he must spend in the field making repairs. Whereas the frequency of striking rocks is not as great as in some situations, the weight of sugar beet harvesters renders the harvester especially vulnerable to breakage when a rock is struck. Largely because of this, and the intricate design of sugar beet harvesters, manufacturers of sugar beet harvesters have ignored the problem and have simply left it up to the individual farmer to take care of the problem as it arises. Of course, some farmers are troubled more than others, for subsoil conditions vary quite widely as far as sugar beet fields are concerned. Where rocks do have a habit of working themselves upwardly in a given field, that particular farmer experiences a considerable amount of down time and the need exists for a simple system that will adequately safeguard against breakage caused by submerged rocks.